Semiconductor integrated circuit, semiconductor integrated circuit module and information apparatus

ABSTRACT

A semiconductor integrated circuit driven by an external power, comprises a change unit whose state changes with lapse of time without the external power, an output unit configured to output a signal in response to an instruction issued when the external power is supplied, the signal indicating a change of the state of the change unit, and an execution unit configured to execute a process in response to the signal. Therefore, the circuit is capable of utilizing time-point/time-period information even if they are not supplied with power.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. 2002-373563, filed Dec.25, 2002, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a semiconductor integratedcircuit, a semiconductor integrated circuit module and an informationapparatus, which utilize information concerning a time period and point.

[0004] 2. Description of the Related Art

[0005] Semiconductor integrated circuits for use in informationapparatuses are driven by electric power. Most information apparatusesare connected to an AC power supply via a cable, or to a battery, andpower is supplied therefrom to semiconductor integrated circuitsincorporated in the apparatuses.

[0006] On the other hand, some information apparatuses acquire powerfrom electromagnetic waves, utilizing electromagnetic induction. Thispower is supplied to the semiconductor circuits incorporated therein tooperate them. In light of the physical conformation or use, theseinformation apparatuses are suitable for radio tags, non-contact ICcards, etc. that cannot incorporate batteries.

[0007] Radio tags and non-contact IC cards are equipped with an IC chipand antenna and no batteries. They are operated by an electromotiveforce that results from electromagnetic induction based on Fleming'slaw. Non-contact IC cards are of the same shape as standard magneticcash cards. On the other hand, radio tags have various shapes.Non-contact IC cards or radio tags, called “a adjacent /vicinity type”,are accessible at a distance of approx. 1 m at maximum. Non-contact ICcards are standardized by ISO/IEC14443 (adjacent type) and ISO/IEC15693(vicinity type). Most radio tags are based on these standards (see, forexample, Jpn. Pat. Appln. KOKAI Publication No. 10-135882).

[0008] Typical systems utilizing such an information apparatus as theabove are, for example, a shoplifting prevention system, in which a gatethat generates electromagnetic waves is provided at the exit of a shop,and radio tags are attached to exhibited articles, or an automaticticket gate system, in which automatic ticket checkers that generateelectromagnetic waves are provided at ticket gates, and non-contact ICcards are used as commuter passes.

[0009] Information apparatuses utilizing electromagnetic induction byelectromagnetic waves are not intended to always receive electromagneticwaves, but receive them only when necessary (only when they are used).In other words, the information apparatuses are not supplied with powerwhen they are not used.

[0010] To control, for example, the period of use of an informationapparatus that is supplied with power only when it is used, there weresome methods, such as a method for managing the period of use at anapparatus that supplies electromagnetic waves, or a method for supplyingtime data together with electromagnetic waves to an informationapparatus to enable it to use the time data. In both methods, theinformation apparatus depends on the power supply apparatus, which meansthat users of the power supply apparatus can illegally use theinformation apparatus by a simple modification of the power supplyapparatus. Therefore, there is a need for a highly reliablesemiconductor integrated circuit that enables information apparatuses toacquire correct time data used for control without depending on powersupply apparatuses.

BRIEF SUMMARY OF THE INVENTION

[0011] The present invention has been developed in light of the abovecircumstances, and aims to provide a semiconductor integrated circuit, asemiconductor integrated circuit module and an information apparatuscapable of utilizing time-point/time-period information even if they arenot supplied with power.

[0012] According to a first aspect of the invention, there is provided asemiconductor integrated circuit driven by an external power,comprising: a change unit whose state changes with lapse of time withoutthe external power; an output unit configured to output a signal inresponse to an instruction issued when the external power is supplied,the signal indicating a change of the state of the change unit; and anexecution unit configured to execute a process in response to thesignal.

[0013] According to a second aspect of the invention, there is provideda semiconductor integrated circuit module comprising:

[0014] a semiconductor integrated unit including:

[0015] a power supply which acquires a current from an antenna, andrectifies and smoothes a acquired current, and supplying, as a power, arectified and smoothed current to an interior of the semiconductorintegrated unit;

[0016] a change unit whose state changes with lapse of time without thepower;

[0017] an output unit configured to output a signal in response to aninstruction issued when the power supply supplies the power, the signalindicating a change of the state of the change unit; and

[0018] an execution unit configured to execute a process in response tothe signal;

[0019] a sealing material which seals the semiconductor integrated unit;and

[0020] an antenna terminal which connects the power supply to theantenna, the antenna terminal being exposed on an outer surface of thesealing material.

[0021] According to a third aspect of the invention, there is providedan information apparatus comprising: an antenna which acquires a currentinduced by electromagnetic induction; a power supply connected to theantenna, the power supply acquiring a current, rectifying and smoothingthe acquired current, and supplying, as a power, a rectified andsmoothed current to an interior of the information apparatus; a changeunit whose state changes with lapse of time without the power from thepower supply; an output unit configured to output a signal in responseto an instruction issued when the power supply supplies the power, thesignal indicating a change of the state of the change unit; and anexecution unit configured to execute a process in response to thesignal.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0022]FIG. 1 illustrates the whole system for which an informationapparatus according to an embodiment of the invention is used;

[0023]FIGS. 2A, 2B, 2C and 2D illustrate an example of a non-contact ICcard 20;

[0024]FIG. 3 is a block diagram illustrating the internal functionblocks of an IC chip 22 incorporated in the IC card 20;

[0025]FIG. 4 is a block diagram illustrating the basic concept of atimer 37;

[0026]FIG. 5 shows a first example that realizes the basic concept ofthe timer 37;

[0027]FIG. 6 illustrates changes with lapse of time in the state of atimer 37-1;

[0028]FIG. 7 is a graph illustrating the relationship between the timeand the output signal of the timer 37-1;

[0029]FIG. 8 is a second example that realizes the basic concept of thetimer 37;

[0030]FIG. 9 is a third example that realizes the basic concept of thetimer 37;

[0031]FIGS. 10A and 10B show connection examples of timer 37 and controlcircuit 34;

[0032]FIG. 11 is a schematic flowchart illustrating an operation of thecontrol circuit 34;

[0033]FIG. 12 illustrates a table 91;

[0034]FIG. 13 is a schematic flowchart illustrating another operation ofthe control circuit 34;

[0035]FIG. 14 is a block diagram illustrating the functions of an ICchip 22′ that is a modification of the IC chip 22;

[0036]FIG. 15 is a schematic flowchart illustrating another operation ofa control circuit 93; and

[0037]FIG. 16 is a graph illustrating the characteristics, i.e., changesin state with lapse of time, of timers 37 and 92.

DETAILED DESCRIPTION OF THE INVENTION

[0038] An embodiment of the invention will be described in detail withreference to the accompanying drawings.

[0039]FIG. 1 shows the whole system to which an information apparatusaccording to an embodiment of the invention is applied. The informationapparatus is, for example, a radio tag or non-contact IC card. In thistext, only non-contact IC card examples will be described.

[0040] The system shown in FIG. 1 comprises an IC card reader/writer 10connected to a server computer (not shown), and a non-contact IC card20. When the non-contact IC card 20 is located close to the IC cardreader/writer 10, a current is generated in the IC card 20 byelectromagnetic induction, i.e., by electromagnetic waves supplied fromthe reader/writer 10. Thus, the non-contact IC card 20 is operablewithout a battery.

[0041] As shown in FIG. 1, the IC card reader/writer 10 comprises atransmission unit 11 for modulating a command transmitted superposed onelectromagnetic waves, a transmission loop antenna 12 connected to thetransmission unit 11 for generating, to the outside, electromagneticwaves with a command superposed thereon, a reception loop antenna 13 forreceiving electromagnetic waves with data superposed thereon from theoutside, and a receiving unit 14 for decoding the data superposed on theelectromagnetic waves received by the reception loop antenna 13, andtransferring the decoded data to a server.

[0042] The non-contact IC card 20 comprises a transmission/receptionloop antenna 21 for receiving electromagnetic waves supplied from thetransmission loop antenna 12 of the IC card reader/writer 10, andtransmitting electromagnetic waves to the reception loop antenna 13, andan IC chip 22 connected to the transmission/reception loop antenna 21.The IC chip 22 will be described later in more detail.

[0043]FIG. 2A shows the outward appearance of an example of thenon-contact IC card 20, FIG. 2B shows the internal structure of thecard, FIG. 2C is a side view of an IC module incorporated in the card,and FIG. 2D is a rear view of the IC module. The non-contact IC card 20is generally a thin card. Therefore, the IC chip 22, which is obtainedby forming a circuit block, described later, integral with a chip as onebody, is sealed in a sealing material 23 (except for the lines led fromthe block and connected to the transmission/reception loop antenna 21),thereby providing an IC module protected from, for example, externalforces. The lines connected to the transmission/reception loop antenna21 extend from two contacts 24 exposed on the outer surface of the ICmodule.

[0044]FIG. 3 is a block diagram illustrating the internal functionblocks of the IC chip 22.

[0045] A rectifier circuit 31 rectifies the current generated by thetransmission/reception loop antenna 21 when it receives electromagneticwaves. A smoothing circuit 32 smoothes the rectified current andsupplies it to each element in the IC chip 22.

[0046] A demodulation circuit 35 receives and demodulates the currentgenerated by the transmission/reception loop antenna 21, therebyacquiring the command supplied from the IC card reader/writer 10 andsupplying it to a control circuit 34.

[0047] A modulation circuit 26 modulates the data output from thecontrol circuit 34 to enable it to be superposed on electromagneticwaves and to be generated to the outside. The resultant current issupplied to the transmission/reception antenna 21, which, in turn,generates electromagnetic waves.

[0048] A memory 33 is a non-volatile semiconductor memory, EEPROM.

[0049] A timer 37 indicates whether or not a predetermined period oftime has passed, and changes its state with lapse of time during timemeasurement without power. In other words, the timer changes its stateeven if the non-contact card 20 is sufficiently away from the IC cardreader/writer 10 such that no current occurs.

[0050] The timer 37 will be described in detail.

[0051]FIG. 4 illustrates the basic concept of the timer 37. The timer 37comprises: a change unit 41, the state of which changes with lapse oftime without a power supply such as a battery; an input unit 42 forinputting a input signal to the change unit 41; and an output unit 43for outputting an output signal changed relative to the input signal inaccordance with the state of the change unit 41. The state of the changeunit 41 changes with lapse of time, and its changed state is used formeasuring time. The input and output units 42 and 43 are used to confirmthe state of the change unit 41.

[0052]FIG. 5 shows a first example 37-1 that realizes the basic conceptof the timer 37.

[0053] The first timer example 37-1 comprises: a first layer having asource region 51, drain region 52 and channel region 53 therebetween; asecond layer provided on the first layer and formed of a tunnelinsulation film 54; a third layer provided on the second layer andformed of a floating gate 55; a fourth layer provided on the third layerand formed of an insulation film 56; and a fifth layer provided on thefourth layer and formed of a control gate 57. A source electrode 58 anddrain electrode 59 are provided on the source and drain regions 51 and52, respectively.

[0054]FIG. 6 illustrates changes with lapse of time in the state of thetimer 37-1. In the figure, hatched circles indicate electrons, and whitecircles indicate positive holes.

[0055] State 1 is an initial state. In the timer 37-1, a pre-process isperformed, in which the control gate 57 applies a high electric fieldbetween the substrate boundary of the channel region 53 and the floatinggate 55, thereby injecting electrons from the channel into the floatinggate 55 utilizing FN tunneling. At this time, positive holes gather atthe substrate boundary of the channel region 53, whereby a channel isformed on the substrate boundary between the source and drain regions 51and 52.

[0056] This pre-process may be performed when, for example, thesemiconductor integrated circuit of the embodiment is manufactured, orwhen a device, such as a card, incorporating the semiconductorintegrated circuit is issued or sold, or when the records in the deviceare updated. The device functions as an entrance ticket, commuter pass,one-day ticket or two-day limited express ticket. It is also assumedthat the pre-process is performed periodically, for example, at 8 a.m.every day. Further, the pre-process may be performed when a product thatcontains the semiconductor integrated circuit requires maintenance work.

[0057] The electrons in the floating gate 55 gradually shift, by directtunneling, to the substrate boundary, thereby reducing the level of theelectric field at the substrate boundary in the channel region 53,compared to the state 1. State 2 is assumed at a time point T₁ a certaintime period after the state 1. State 3 is assumed at a time point T₂ acertain time period after the state 2. Similarly, state 4 is assumed ata time point T₃ a certain time period after the state 3. The circlesindicated by the broken lines represent the shift of electrons made dueto direct tunneling by the respective time points. In the state 4 at thetime point T₃, most electrons escape from the floating gate 55,therefore the channel at the substrate boundary of the channel region 53disappears. As a result, no signals are output.

[0058]FIG. 7 is a graph illustrating the relationship between the timeand the output signal of the timer 37-1. Direct tunneling occurs betweentime points T_(a) (=0) and T_(b), and lastly, the channel disappears,whereby the level of the output signal is reduced to the noise level.Since the timer 37-1 supplies an output signal corresponding to a changein level between T_(a) (=0) and T_(b) (=the time when the output signallevel reaches the noise level), the side for receiving the output signalcan determine whether or not a predetermined time period has elapsed, orcan determine a specific time point (e.g. T₁, T₂ or T₃ shown in FIG. 7)a predetermined time period after the initial state if the relationshipbetween the state of the timer 37-1 and the level of the output signalis always clear. The time points T₁, T₂ and T₃ correspond to the states2, 3 and 4 in FIG. 6.

[0059]FIG. 8 is a second example 37-2 that realizes the basic concept ofthe timer 37 of FIG. 4. The timer 37-2 comprises: a first layer having asource region 61, drain region 62 and channel region 63 therebetween; asecond layer provided on the first layer and formed of a tunnelinsulation film 64; a third layer provided on the second layer andformed of a gate 65; and a PN junction provided on the third layer forcontrolling a leak current. A source electrode 68 and drain electrode 69are provided on the source and drain regions 61 and 62, respectively.

[0060] The change in the state of the timer 37-2 with lapse of time issimilar to that of the timer 37-1, although in the former, currentleakage occurs in a PN junction, and in the latter, direct tunnelingoccurs. Therefore, no description is given of the change in the state ofthe timer 37-2 with lapse of time.

[0061]FIG. 9 is a third example 37-3 that realizes the basic concept ofthe timer 37 of FIG. 4. The timer 37-3 comprises: a first layer having asource region 71, drain region 72 and channel region 73 therebetween; asecond layer provided on the first layer and formed of a tunnelinsulation film 74; a third layer provided on the second layer andformed of a gate 75; and a Schottky junction 76 provided on the thirdlayer for controlling a leak current. A source electrode 78 and drainelectrode 79 are provided on the source and drain regions 71 and 72,respectively.

[0062] The change in the state of the timer 37-3 with lapse of time issimilar to that of the timer 37-1, although in the former, currentleakage occurs in a Schottky junction, and in the latter, directtunneling occurs. Therefore, no description is given of the change inthe state of the timer 37-3 with lapse of time.

[0063] As described above, a pre-process for forming a channel is neededbefore time measurement is started by the timer 37 (hereinafter, thetimer 37 represents the timers 37-1, 37-2 and 37-3). If, however, anyonecan perform the pre-process, a security risk arises. To avoid this,authentication to confirm as to whether or not the IC card reader/writer10 is legal, which is often performed for standard IC cards, may beemployed. In this case, only when the reader/writer 10 is determined tobe legal, the pre-process is performed and time measurement is started.

[0064] The above-described timer 37 is connected to the control circuit34. FIGS. 10A and 10B show examples of connection of the timer 37 andcircuit 34.

[0065] In the case of FIG. 10A, when the smoothing circuit 32 suppliespower to the timer 37, a voltage occurs between the opposite ends of thetimer 37. A power supply terminal 81 is connected to the sourceelectrode 58, 68, 78 of the timer 37 via a switch element 83, while aGND terminal 82 is connected to the drain electrode 59, 69, 79 via anampere meter 84.

[0066] The switch element 83 is connected to an ON/OFF (enable) signalline led from the control circuit 34, and is turned on when an ON signalis supplied. The ampere meter 84 is connected to output a current valueto the control circuit 34.

[0067] When the control circuit 34 turns on the switch element 83 toconfirm the state of the timer 37 during the operation of the IC chip22, a predetermined voltage is applied between the power supply terminal81 and GND terminal 82, whereby the ampere meter 84 measures the currentflowing through the timer 37 and outputs the measurement result to thecontrol circuit 34. As a result, the control circuit 34 detects thestate of the timer 37.

[0068] In the above connection example, a single timer 37 is employed.However, a plurality of timers 37 may be employed. The change with lapseof time in the state of the change unit 41 of one timer 37 may be thesame as or different from that of the change unit 41 of another timer37, according to purpose. Referring now to FIG. 10B, a description willbe given of the case where the timers 37 show the same change in statewith lapse of time. In this example, a plurality of timers 37 similar tothat shown in FIG. 10A are arranged parallel to each other, the currentvalues output from them are input to an averaging circuit 85, and theaveraged current is output from the circuit 85 to the control circuit34. The ON/OFF (enable) signal line led from the control circuit 34 isconnected to the respective switch elements 83 to make them be commonlycontrolled by the control circuit 34. In this example, even if thechange units 41 of the timers 37 exhibit some different changes in statewith lapse of time, their average value enables a stable timer to berealized. Further, if change units 41 that show different changes instate with lapse of time are employed (this case is not shown), varioustypes of time information can be acquired, for example.

[0069] The control circuit 34 is connected to the demodulation circuit35 to receive therefrom a demodulated command, and is also connected tothe modulation circuit 36 to output thereto a process result based onthe command. Further, the control circuit 34 is connected to the timer37 as shown in the connection example. A command supplied to the controlcircuit 34 is, for example, a command to read an ID dedicated to the ICchip 22 (or IC card 20), from which the chip (or card) can be directlyidentified, or a command to write information, such as the name of astation from which a train or the like has been utilized.

[0070] The control circuit 34 incorporates a CPU, ROM and RAM, which arenot shown. The CPU operates in accordance with a program prestored inthe ROM, using the RAM as a work memory. Referring to FIG. 11, theoperation of the control circuit 34 will be described roughly.

[0071] Firstly, the control circuit 34 receives a command from thedemodulation circuit 35 (S101). Subsequently, the control circuit 34refers to the timer 37 (S102). Concretely, an ON signal to input to thetimer 37 to acquire a current value therefrom. The control circuit 34determines from the current value whether or not the command should beprocessed (S103). The determination at the step S103 is, for example, asto whether or not the current value (level) is equal to (or less than)the noise level shown in FIG. 7. If the current level is equal to thenoise level, this means that a predetermined time period has passed,while if it is higher than the noise level, it means that thepredetermined time period (T_(b) in FIG. 7) has not yet passed.

[0072] If it is determined that the command should be processed, thecommand is processed (S104). The control circuit 34 supplies the processresult to the modulation circuit 36 (S105). If it is determined that thecommand should not be processed, another predetermined process (forexample, a process for informing that the card has expired) isperformed, or no process is performed (S106). The step S106 indicatesthat a desired process is not performed.

[0073] The above-described operation of the control circuit 34 is justone example. In another example, described referring to FIG. 7, in whichthe relationship between the state of the timer 37 and the level of theoutput signal is clearly followed, the time period elapsing from theinitial state can be acquired. Therefore, a command can be processedusing time information. In this case, if a time information table 91that stores current value (output signal level) ranges in relation totime information, as shown in FIG. 12, is held in the ROM of the controlcircuit 34, time information corresponding to each current value can beutilized for processing a command. This will be described in more detailwith reference to the flowchart of FIG. 13.

[0074] Firstly, the control circuit 34 receives a command from thedemodulation circuit 35 (S201). Subsequently, the control circuit 34refers to the timer 37 to acquire a current value (S202). After that,the control circuit 34 acquires time data corresponding to the acquiredcurrent value, from the time information table 91 in the ROM (S203). Inaccordance with the program stored in the RAM, the control circuit 34processes the command supplied from the demodulation circuit 35 (S204).This process is assumed to include a process utilizing the acquired timedata. The control circuit 34 transmits the process result to themodulation circuit 36 (S205).

[0075] If the control circuit 34 is made to operate as described above,it can utilize time data. Although the embodiment utilizes the timeinformation table 91 to acquire time data, the embodiment of theinvention is not limited to this. For example, a function f(c) may bestored, which uses, as a variable, a current value (c) that varies asshown in the graph of FIG. 7, thereby acquiring time data by calculationusing the function f(c).

[0076] Further, although in the embodiment, attention has been paid tothe use of only time information, the flowcharts of FIGS. 11 and 13 maybe combined so that both term and time information can be used forcommand processing.

[0077] As described above in detail, if the IC chip 22 of the embodimentis applied to, for example, a non-contact IC card or radio tag thatcannot always be supplied with power, it performs command processingwhen it is supplied with power, and the timer employed in the chipcontinues to change its state until a predetermined time period passeseven when the chip is supplied with no power. On the basis of the timedata obtained from the timer and indicative of a predetermined elapsedtime period, a determination as to whether or not command processingshould be performed, or other data processes can be performed, is made.In other words, the embodiment of the invention can provide an IC chipthat incorporates a semiconductor capable of measuring time even if nopower is supplied thereto, and capable of using the measuredtime-period/time-point when power is supplied. The IC chip with thetimer function does not need a power supply line or GND line to beconnected to an external power supply, therefore can be provided in theform of a sealed module with only an antenna contact exposed to theoutside, like the conventional non-contact IC cards that do not needbatteries.

[0078] A modification of the IC chip 22 will now be described.

[0079]FIG. 14 is a block diagram illustrating the functions of an ICchip 22′ that is a modification of the IC chip 22. The IC chip 22′differs from the above-described IC chip 22 in that the formerincorporates a timer 92 as well as the timer 37. The timer 92 has thesame structure as the timer 37 but shows different changes in state withlapse of time. Different changes in state with lapse of time can berealized by, for example, modifying the first example of FIG. 5 suchthat the degree of tunneling in the tunnel insulation film 54 isdifferent from that in the first example, or such that the number ofelectrons accumulated in the floating gate 55 in the initial state isdifferent.

[0080] A control circuit 93 incorporated in the IC chip 22′ additionallyincorporates a connection unit used to refer to the timer 92, and twotimers similar to that shown in FIG. 10A are employed. These pointsdiffer from the IC chip 22. In addition, the program stored in the ROMis changed.

[0081] Specifically, the program is changed to perform more accuratetime control using the two timers 37 and 92. FIG. 15 illustrates anotheroperation of the control circuit 93 based on the changed program. In thefollowing description, it is assumed that the timer 92 reaches the noiselevel much earlier than the timer 37, and term information is utilizedinstead of time-point information.

[0082] Firstly, the control circuit 93 receives a command from thedemodulation circuit 35 (S301). Subsequently, the control circuit 93refers to the timer 92 (S302). The control circuit 93 determines whetheror not the current value acquired from the timer 92 is equal to (or lessthan) the noise level (S303). If the current level is equal to the noiselevel, the control circuit 93 refers to the timer 37 (S304). The controlcircuit 93 determines whether or not the current value acquired from thetimer 37 is equal to (or less than) the noise level (S305). If thecurrent level is higher than the noise level, the control circuit 93processes the command (S306), and outputs the process result to themodulation circuit 36 (S307).

[0083] If it is determined at the step S303 that the current level ishigher than the noise level, or if it is determined at the step S305that the current level is equal to or less than the noise level, it isdetermined that the command-processing allowable term of the card isexceeded, with the result that another predetermined process (forexample, a process for informing that the card has expired) isperformed, or no process is performed (S308).

[0084]FIG. 16 is a graph illustrating the characteristics (i.e., changesin state with lapse of time) of the timers 37 and 92 that are related tothe above-described time management. As shown, when the timer 92 hasmeasured a predetermined term (Ts), a state in which command processingcan be performed is assumed. After that, until the timer 37 has measureda predetermined term, the command-processing enabled state is continued.When the timer 37 has measured the predetermined term (Tb), a state inwhich command processing cannot be performed is assumed.

[0085] In this modification, it is determined, using the two timers 37and 92, whether or not a command from the IC card reader/writer 10should be processed. However, this may be modified such that twocommand-processing programs are stored in the ROM of the control circuit92 for each command supplied from the IC card reader/writer 10, and oneof the two program that corresponds to the term including the commandreceiving time is executed. This enables various types of control. TheIC chip 22′ according to the modification of the embodiment provides, aswell as the above-mentioned advantages of the embodiment, the advantagethat when a predetermined valid term is set, its start time can also beset.

[0086] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. A semiconductor integrated circuit driven by anexternal power, comprising: a change unit whose state changes with lapseof time without the external power; an output unit configured to outputa signal in response to an instruction issued when the external power issupplied, the signal indicating a change of the state of the changeunit; and an execution unit configured to execute a process in responseto the signal.
 2. The semiconductor integrated circuit according toclaim 1, wherein the output unit includes a plurality of outputelements, each of the output elements outputting the signal in responseto the instruction.
 3. The semiconductor integrated circuit according toclaim 1, wherein the change unit includes a plurality of changeelements, each of the change elements whose state changes with lapse oftime without the external power.
 4. The semiconductor integrated circuitaccording to claim 3, wherein the output unit includes a plurality ofoutput elements, each of the output elements outputting the signal inresponse to the instruction.
 5. The semiconductor integrated circuitaccording to claim 1, further comprising a control unit configured toacquire time information based on the signal when the external power issupplied, and control the execution unit to make it execute the processusing the time information.
 6. The semiconductor integrated circuitaccording to claim 5, wherein the output unit includes a plurality ofoutput elements, each of the output elements outputting the signal inresponse to the instruction.
 7. The semiconductor integrated circuitaccording to claim 5, wherein the change unit includes a plurality ofchange elements, each of the change elements whose state changes withlapse of time without the external power.
 8. The semiconductorintegrated circuit according to claim 7, wherein the output unitincludes a plurality of output elements, each of the output elementsoutputting the signal in response to the instruction.
 9. Thesemiconductor integrated circuit according to claim 1, furthercomprising: an antenna connection unit connected to an antenna andconfigured to acquire a current induced in the antenna byelectromagnetic induction; and a power supply connected to the antennaconnection unit, the power supply acquiring the current, rectifying andsmoothing a acquired current, and supplying a rectified and smoothedcurrent to an interior of the semiconductor integrated circuit.
 10. Thesemiconductor integrated circuit according to claim 9, wherein thechange unit includes a plurality of change elements, each of the changeelements whose state changes with lapse of time without the externalpower, and the output unit includes a plurality of output elements, eachof the output elements outputting the signal in response to theinstruction.
 11. The semiconductor integrated circuit according to claim9, further comprising: a control unit configured to control theexecution unit to make it execute the process based on the signal; ademodulation unit configured to demodulate a command superposed on theacquired current and output the command to the control unit, thedemodulation unit being connected to the antenna connection unit; and amodulation unit configured to modulate a result of the process andoutput a modulated result to the antenna.
 12. The semiconductorintegrated circuit according to claim 5, further comprising: an antennaconnection unit connected to an antenna and configured to acquire acurrent induced in the antenna by electromagnetic induction; and a powersupply connected to the antenna connection unit, the power supplyacquiring the current, rectifying and smoothing a acquired current, andsupplying a rectified and smoothed current to an interior of thesemiconductor integrated circuit.
 13. The semiconductor integratedcircuit according to claim 12, wherein the change unit includes aplurality of change elements, each of the change elements whose statechanges with lapse of time without the external power, and the outputunit includes a plurality of output elements, each of the outputelements outputting the signal in response to the instruction issuedwhen the external power is supplied.
 14. The semiconductor integratedcircuit according to claim 12, further comprising: a demodulation unitconfigured to demodulate a command superposed on the acquired currentand output the command to the control unit, the demodulation unit beingconnected to the antenna connection unit; and a modulation unitconfigured to modulate a result of the process and output a modulatedresult to the antenna.
 15. A semiconductor integrated circuit modulecomprising: a semiconductor integrated unit including: a power supplywhich acquires a current from an antenna, and rectifies and smoothes aacquired current, and supplying, as a power, a rectified and smoothedcurrent to an interior of the semiconductor integrated unit; a changeunit whose state changes with lapse of time without the power; an outputunit configured to output a signal in response to an instruction issuedwhen the power supply supplies the power, the signal indicating a changeof the state of the change unit; and an execution unit configured toexecute a process in response to the signal; a sealing material whichseals the semiconductor integrated unit; and an antenna terminal whichconnects the power supply to the antenna, the antenna terminal beingexposed on an outer surface of the sealing material.
 16. Thesemiconductor integrated circuit module according to claim 15, whereinthe output unit includes a plurality of output elements, each of theoutput elements outputting the signal in response to the instructionwhen the power is supplied.
 17. The semiconductor integrated circuitmodule according to claim 15, wherein the semiconductor integrated unitfurther includes: a control unit configured to control the executionunit to make it execute the process based on the signal; a demodulationunit configured to demodulate a command superposed on the acquiredcurrent and output the command to the control unit, the demodulationunit being connected to the antenna terminal; and a modulation unitconfigured to modulate a result of the process and output a modulatedresult to the antenna.
 18. The semiconductor integrated circuit moduleaccording to claim 15, further comprising a control unit configured toacquire time information based on the signal, and control the executionunit to make it execute the process using the time information.
 19. Thesemiconductor integrated circuit module according to claim 18, whereinthe output unit includes a plurality of output elements, each of theoutput elements outputting the signal in response to the instructionwhen the power is supplied.
 20. The semiconductor integrated circuitmodule according to claim 18, wherein the semiconductor integrated unitfurther includes: a control unit configured to control the executionunit to make it execute the process based on the signal; a demodulationunit configured to demodulate a command superposed on the acquiredcurrent and output the command to the control unit, the demodulationunit being connected to the antenna terminal; and a modulation unitconfigured to modulate a result of the process and output a modulatedresult to the antenna.
 21. An information apparatus comprising: anantenna which acquires a current induced by electromagnetic induction; apower supply connected to the antenna, the power supply acquiring acurrent, rectifying and smoothing the acquired current, and supplying,as a power, a rectified and smoothed current to an interior of theinformation apparatus; a change unit whose state changes with lapse oftime without the power from the power supply; an output unit configuredto output a signal in response to an instruction issued when the powersupply supplies the power, the signal indicating a change of the stateof the change unit; and an execution unit configured to execute aprocess in response to the signal.
 22. The information apparatusaccording to claim 21, wherein the change unit includes a plurality ofchange elements, each of the change elements whose state changes withlapse of time without the power, and the output unit includes aplurality of output elements, each of the output elements outputting thesignal in response to the instruction when the power is supplied. 23.The information apparatus according to claim 21, further comprising: acontrol unit configured to control the execution unit to make it executethe process based on the signal; a demodulation unit configured todemodulate a command superposed on the acquired current and output thecommand to the control unit, the demodulation unit being connected tothe antenna; and a modulation unit configured to modulate a result ofthe process and output a modulated result to the antenna.
 24. Theinformation apparatus according to claim 21, further comprising acontrol unit configured to acquire time information based on the signal,and control the execution unit to make it execute the process using thetime information.
 25. The information apparatus according to claim 24,wherein the change unit includes a plurality of change elements, each ofthe change elements whose state changes with lapse of time without thepower, and the output unit includes a plurality of output elements, eachof the output elements outputting the signal in response to theinstruction issued when the power is supplied.
 26. The informationapparatus according to claim 24, further comprising: a control unitconfigured to control the execution unit to make it execute the processbased on the signal; a demodulation unit configured to demodulate acommand superposed on the acquired current and output the command to thecontrol unit, the demodulation unit being connected to the antenna; anda modulation unit configured to modulate a result of the process andoutput a modulated result to the antenna.